Releasable sucker rod connection



Patented June 10, 1941 UNITED spares ears-nr cerise EELEASABLE `SUCEUSE?. 1BGD -CONNEGT'IN Russell Livei'gced, lHcustcn, Tex.

Application December 5, i938, Serial No. 244,010

(El. 10S- 1226) 5 Claims.

tageous to disconnect 4the sucker rod from the I pump plunger and to remove such rod separately from the tubing string. If it is desired to remove the plunger and sucker rod before pulling the string, 'difficulty is frequently encountered because'of the destructive effect produced upon the plunger in pullingsuch plunger through Vthe tubing string together with the sucker rod.

It is a general object of the present invention to provide a. practical device for attaching and detaching the sucker rod and the plunger reciprocated thereby in order to avoid indicated difficulties.

It is also an object to provide a releasable connection between parts of the reciprocating asn sembly of a well pump, such connection being so constructed that release will take place automatically upon lifting of the assembly to a predetermined level.

It is also an object to provide a positive yet releasable connection between the sucker rod and the pump plunger.

Still another object is to provide a releasabie connection which is released by cooperation with an inwardly extending projection within the tubting string when the sucker rod and plunger asf As illustrated in the drawing the invention r comprises a tubing string I including sections 2 and 3 interconnected by means of a special coupling 4 having an inward annular projection 5 formed by the downwardly depending surface 6 and a downwardly facing shoulder 'I.

The section 3 `serves as a pump cylinder and receives the pump plunger I0 which is placed therein preliminary to the lowering of the tubing string into the well. As has already been indicated it is the purpose of the invention'to provide a releasable connection between the plunger IIJ and the sucker rod II so that the sucker rod. may bealowered within the tubing string I after such string has been placed in the desired position within the well. Likewise-the construction is designed to enable removal of the sucker rod I I preliminary to withdrawal of the tubing string I from the well.

In order to provide the desired connection the lower end of the sucker rod II is provided with a section I2 of special configuration, such section being attached to the sucker rod II by means of the threads I3. The lower end of the section I2 Vis provided with a head VI5 which is formed by downwardly and inwardly tapered face i6 which merges into downwardly tapered portion Il terminating in a rounded end extremity it.

A connector generally designated as 'Ztl is attached to the plunger Il). This connector includes Ia bushing -25 which is counterbored at its upper'end and slotted at 25 to provide resilient fingers 21 having tapering inner and outer faces 28 and 29 at their upper ends to serve a purpose that will be more fully apparent.

Below the counterbore the bushing 25 is reduced in cross section to form a downwardly facing shoulder 30. The lower end of the reduced portion terminates in a stern 3f! through which the bushing is connected to the plunger' A sleeve 40 surrounds the bushing 25 and has an inwardly extending flange 4I at its lower end which slides over the reduced portion of the bushing 25 and engages the shoulder 33 to limit upward movement of the slee-ve relative to the bushing. At its upper end the sleeve 4G is provided with an inner tapering surface which is complementary to the outer tapered surface on the fingers 21. It is believed apparent that whenever the sleeve i0 surrounds the bushing '25 as shown in Fig. 1, the fingers 2l are restrained against outward movement by virtue of the complementary tapered surface on these members. This is the normal relative position of the bushing 25 and the sleeve 40 since the sleeve is constantly urged upwardly against the shoulder 30 by means of a spring 42 surrounding the bushing 25 and held in tension by means of a collar 30 fixed on the stem 3| by any suitable means such as threads 43 and set screw 44.

Within the counterbore in the bushing 25 there is positioned a slip member I! which, similar to the bushing 25, is also counterbored and slotted to provide ingers 5I having inner and outer tapered faces which are complementary to the surface 2S on the bushing 25 and the surface I1 on the head I5. This slip member is provided with an opening at its lower end to receive a cap screw 55 having a threaded connection 56 in the bottom of the counterbore in the bushing 25. A spring 51 surrounds the cap screw 55 and constantly urges the slip member 50 upwardly sol that the ngers 5I are held in their innermost position.

The mode of operation and the advantages attained by use of the construction just described are believed apparent from the foregoing description. As already indicated the plunger I Il will be positioned within the -tubirfg section 3 and lowered into the well with the tubing string. The section I2 is then attached to the sucker rod and is lowered into the well. When the head I5 reaches the collar 4 it is guided to the center of the tubing string by virtue of the tapered surface 6 and also tapered surface I 9 on the bushing 25. The head I5 therefore makes engagement with the` slip member 5D which is urged downwardly against the force exerted by the spring 51. As the slip member 5I! passes downwardly from the tapered surface 28 of the bushing 25 the force exerted thereon by the head I5 will cause the fingers 5I to move outwardly and permit the head I5 to enter the slip member. As soon as the head enters the slip member the face l5 engages the conical surface I9 and the slip member 58 moves upwardly under the influence of the spring 51 to tightly wedge between the tapered surface 28 and the surface of the head I5. In this manner a rigid connection between the connector 2|) and the sucker rod is effected, anad acts in the same manner as the usual connection of the sucker rod string to the pump plunger so long as reciprocation of the assembly takes place below the coupling 4 in the tubing string.

When it is desired to disconnect the sucker rod from the pumpplunger I0, the sucker rod string is elevated until the sleeve 40 engages the shoulder 1. Further lifting of the assembly causes compression of the spring 42 and the bushing moves upwardly relative to the sleeve 4D. Such upward movement of the bushing 25 together with the slip member 5I! therein releases the ngers 21 so that the head I5 causes both the fingers 5I and the iingers 21 to move radially outward, whereby the connection between the sucker rod and the pump plunger is released. The relative position of parts when such release takes place is illustrated in Fig. 2.

Broadly the invention comprehends a releasable connection whereby a sucker rod may be connected to or disconnected from a pump plunger so that the sucker rod and tubing string within a well may be separately removed therefrom.

What is claimed is:

l. In a device of the class described, a tubing string, an assembly including a pump plunger and a sucker rod within said string, a head on the lower end of said sucker rod, an inwardly eX- tending projection in the string adapted to guide the head centrally of the string as the head moves past the projection, and a releasable connection 4between the sucker rod and the plunger, said connection including a member adapted to engage said projection and a fingered bushing movable from within the member to expand and release the sucker rod when the assembly is lifted to a predetermined level within the string.

2. In a pump assembly, a plunger, a sucker rod having a head at its lower end, a bushing attached to the plunger and having fingers adapted to effect engagement with said head, a sleeve surrounding said bushing and slidable longitudinally thereof, and resilient means normally holding said bushing and sleeve in concentric relation to hold the fingers in engaging position.

3, In a pump assembly, a cylinder, a plunger therein, a sucker rod, means attached to said plunger and including resilient ngers for engaging the end of the sucker rod whereby the sucker rod and plunger comprisea composite assembly, means normally holding the fingers in engagement with the sucker rod, and means extending inwardly from the walls of said cylinder for engaging said last mentioned means to disconnect the sucker rod when the assembly has moved to a predetermined level within the cylinder.

4. In a device of the class described, a tubing string, an assembly including a pump plunger and a sucker rod within said string and having a head on its lower end, an inwardly extending projection in the string adapted to guide the head centrally of the string as the head moves past the projection, a releasable connection between the sucker rod and plunger, said connection comprising a member adapted toengage said projection as the assembly is moved upwardly within the string, a fingered member movable from within the iirst mentioned member, said fingered member having an upwardly converging inner surface therein, and a slip member movable within said bushing and having spring ngers with outer surfaces adapted to engage said tapering face whereby the head is rigidly engaged therein.

5. In a device lof the class described wherein a releasable connection is provided between a pump plunger and a head on the lower end of a sucker rod, the combination of a bushing attached 'to the pump plunger and having fingers adapted to move radially thereof, a sleeve surrounding said bushing and slidable longitudinally thereof, resilient means normally holding said bushing and sleeve in concentric relation to hold the lingers in fixed position, said fingers having upwardly converging inner surfaces therein, a slip member within the bushing and having an outer surface adapted to engage said converging surface, and means resiliently supporting the slip member within the bushing so that the head may move into the bushing and enter the slip member to be rigidly engaged thereby.

RUSSELL LIVERGOOD. 

